C4 dicarboxylic acids are utilized not only in various applications in the food industry as an acidulant, an antimicrobial agent and a pH adjusting agent, but also used as a raw material for synthetic resins and biodegradable polymers. Thus, C4 dicarboxylic acids are industrially valuable substances. C4 dicarboxylic acids are industrially produced by either chemical synthesis from petrochemical raw materials or microbial fermentation. Previously, C4 dicarboxylic acids have been mainly produced by chemical synthesis due to a lower cost. However, from the viewpoint of rising costs of the raw materials, the burden on the environment, and the like, production methods by microbial fermentation using a recyclable resource as a raw material have recently been attracting attention.
It is known that fumaric acid, which is one of C4 dicarboxylic acids, can be produced by using a fermentative fungus, such as Rhizopus. Rhizopus produces fumaric acid using glucose as a carbon source, and excretes the produced fumaric acid to the outside of the cell. To date, as techniques for producing fumaric acid with high productivity by using Rhizopus, improvements of culturing methods, and preparations of strains having high productivity by mutation breeding are known. However, since the genetic background of Rhizopus has not yet been well studied, the development of the techniques for producing fumaric acid with high productivity by Rhizopus through gene recombination is not easy and has little information. There are only a few reports for improving fumaric acid productivity by introducing a gene encoding pyruvate carboxylase from Saccharomyces cerevisiae into Rhizopus delemar (Patent Literature 1), or by introducing a gene encoding phosphoenolpyruvate carboxylase from E. coli into Rhizopus oryzae (Non Patent Literature 1).                (Patent Literature 1) CN-A-103013843        (Non Patent Literature 1) Metabolic Engineering, 2012, 14: 512-520        